Consolidated Balance Sheets (Unaudited) (Parentheticals) (USD $) In Thousands	Sep. 30, 2011	Dec. 31, 2010
MGE Energy [Member]
Receivables, Net
Reserve for uncollectible accounts receivable	$ 3,868	$ 3,994
Reserve for uncollectible other accounts receivable	476	595
MGE [Member]
Receivables, Net
Reserve for uncollectible accounts receivable	3,868	3,994
Reserve for uncollectible other accounts receivable	$ 476	$ 595

The valuation allowance as of the balance sheet date to reduce the gross amount of receivables to estimated net realizable value, which would be presented in parentheses on the face of the balance sheet.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Article 7

-Section 03

-Paragraph 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 4

-URI http://asc.fasb.org/extlink&oid=6965416&loc=d3e5074-111524

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-03.(a),5)

-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Name:	us-gaap_AllowanceForDoubtfulAccountsPremiumsAndOtherReceivables
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant